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| author | Johannes Wikner <kwikner@ethz.ch> | 2024-09-23 20:49:34 +0200 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2024-10-10 10:34:29 +0200 |
| commit | 3ea87dfa31a7b0bb0ff1675e67b9e54883013074 (patch) | |
| tree | 5e2d4b48d1427405de974b93921ce54fa428eb56 /arch | |
| parent | x86/cpufeatures: Define X86_FEATURE_AMD_IBPB_RET (diff) | |
| download | linux-3ea87dfa31a7b0bb0ff1675e67b9e54883013074.tar.xz linux-3ea87dfa31a7b0bb0ff1675e67b9e54883013074.zip | |
x86/cpufeatures: Add a IBPB_NO_RET BUG flag
Set this flag if the CPU has an IBPB implementation that does not
invalidate return target predictions. Zen generations < 4 do not flush
the RSB when executing an IBPB and this bug flag denotes that.
[ bp: Massage. ]
Signed-off-by: Johannes Wikner <kwikner@ethz.ch>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/include/asm/cpufeatures.h | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 3 |
2 files changed, 4 insertions, 0 deletions
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index a222a24677d7..913fd3a7bac6 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -524,4 +524,5 @@ #define X86_BUG_DIV0 X86_BUG(1*32 + 1) /* "div0" AMD DIV0 speculation bug */ #define X86_BUG_RFDS X86_BUG(1*32 + 2) /* "rfds" CPU is vulnerable to Register File Data Sampling */ #define X86_BUG_BHI X86_BUG(1*32 + 3) /* "bhi" CPU is affected by Branch History Injection */ +#define X86_BUG_IBPB_NO_RET X86_BUG(1*32 + 4) /* "ibpb_no_ret" IBPB omits return target predictions */ #endif /* _ASM_X86_CPUFEATURES_H */ diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 07a34d723505..f1040cb64841 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1443,6 +1443,9 @@ static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c) boot_cpu_has(X86_FEATURE_HYPERVISOR))) setup_force_cpu_bug(X86_BUG_BHI); + if (cpu_has(c, X86_FEATURE_AMD_IBPB) && !cpu_has(c, X86_FEATURE_AMD_IBPB_RET)) + setup_force_cpu_bug(X86_BUG_IBPB_NO_RET); + if (cpu_matches(cpu_vuln_whitelist, NO_MELTDOWN)) return; |